1. Field of the Invention
The present invention relates generally to a lead member and a secondary battery module having the same, and more particularly to a secondary battery module having a plurality of cells stacked to a predetermined height and lead members diagonally inserted into insulating mediators to connect the cells in series and thereby output a desired battery power for industrial instrument or an electric car.
2. Description of the Related Art
A single unit cell has a limited output and a small power storing capacity. Therefore, a battery module comprising a plurality of cells is generally used in an electric car to secure sufficient power and driving hours.
As shown in FIG. 1, a conventional battery module 1 includes: a plurality of cells 2 disposed side by side; two electrodes 2a provided respectively on two outmost cells 2; two end plates 3 fastened to the outer sides of the two outmost cells; and a plurality of steel bands 4 surrounding the end plates 3 and the cells 2 as a whole.
In the prior art, however, leads 2b used to connect adjacent cells in series are welded to the electrode terminals of the cells, which makes it difficult to fabricate battery modules that meet various power demands for industrial instrument and electric cars.
Since the leads connecting the electrode terminals of adjacent cells in series are exposed, an accidental short circuit may occur in the cells due to an unintended drop of a metal conductor onto the leads, which eventually results in damage of the entire battery module.
Moreover, neither a cell protection circuit nor a safety device is used to protect the battery module against damage caused by abnormal overcurrent, overcharge or overdischarge conditions of the cells.